Software Modeling

The analysis software available is NEC, FEKO and GEMACS as well as EMC Consulting Inc. generated software.

The Numerical Electromagnetic Code (NEC) is a user oriented computer program based on the Method
of Moments (MoM) and written in FORTRAN for the analysis of electromagnetic response of and
radiation from metal structures and antennas. It does not predict scattered , diffracted and creeping
waves. 4NEC2D by Aries provides graphics.

The General Electromagnetic Analysis of GEMACS is an older hybrid analysis program now available in a Windows version. It combines MoM, Uniform Geometrical Theory of diffraction (UTD) and Finite Differences (FD) formalisms in the frequency domain. It does allow diffraction, scattered fields and creeping waves for which it is ideal but cannot perform aperture coupling.

FEKO is a popular electromagnetic analysis program and is a suite of tools used for electromagnetic 3D analysis. FEKO simulations are based on the MoM, Multilevel Fast Multipole Method (MLFMM), Finite Element Method (FEM), Physical Optics(PO) and Uniform Theory of Diffraction (UTD). It can provide easy and accurate aperture coupling but analysis of creeping wave may not be as good as GEMACS. As can be seen from the example, both programs do a good job of analyzing antenna coupling around a cylinder, which can be the fuselage in of the model of an aircraft.

FEKO used to predict the shielding effectiveness of a 540 x 370 x 330
mm shielded copper enclosure with a 200 x 300 mm aperture

Comparison between FEKO results and measurements

FEKO and GEMACS used to predict the coupling with vertical antennas
around 26cm cylinder compared to measurements

NEC used to predict the current flow on a 6.8m wire from
a normalized 1V/m incident field for maximum coupling